Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Evolution of the human brain

  1. Nov 29, 2013 #1
    Lawrence Krauss says that
    We evolved as human beings a few million years ago on the Savanna in Africa and we evolved to escape tigers, or lions, or predators. You know, how to throw a rock or a spear or how to find a cave and we didn't evolve to understand quantum mechanics.
    How correct is the statement

    I feel that that evolution is a continuous process and brain evolves to understand the threats faced
    Please give your opinions
     
    Last edited by a moderator: Dec 22, 2013
  2. jcsd
  3. Nov 29, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    ... where? citation please: context is everything.

    It's pretty good, up to a point ... QM is very recent and there is no record of noticeable changes to human biology in response.

    OTOH: we did evolve to understand the World around us, and to improve that understanding.
    Our understanding of QM is one result of that process. It's just not a major contributing factor to our speciation.

    ...we also have to be careful about the word "purpose" when we are talking about adaptations.

    I suspect he's speaking off the cuff, and just wants to give an idea as to why QM is so counter-intuitive. Its just not the sort of thing that would be life-or-death back when our brain structure was being laid down.

    Depends what you are calling "continuous". It takes a while to get the hang of how evolution happens. Have a look at the role prions play in biodiversity for eg.

    That's just asking for trouble! Instead, ask for the science, and pointers to finding out more.
    Certainly you don't want empty opinions.
     
  4. Nov 29, 2013 #3

    phinds

    User Avatar
    Gold Member

    What he means is we don't live at the quantum level so we have no direct experience of it and so it seems weird. The same is true of things on a cosmological scale. The very very large and the very very small are just not in direct human experience and so our "intuition" and "common sense" often fail completely at those scales.
     
  5. Nov 29, 2013 #4

    bhobba

    Staff: Mentor

    Don't know about you, but I have zero idea how to do any of those things, well maybe throw a rock, but that's pretty trivial, and I certainly understand QM a LOT better than a zero idea.

    The human brain is a pretty versatile thing - its just, as seems quite obvious, as civilization grows we require different skills to be successful. Civilization developed from the exercise of that 'brain power', its hardly surprising the very thing that set us on that path should now take on a greater significance.

    Regarding our understanding of QM, it's not quite as mysterious as it once was:
    http://arxiv.org/pdf/quant-ph/0101012.pdf

    It looks like even that succumbed to our relentless probing.

    I am pretty sure he was simply alluding to the obvious - our hunter gather background has not equipped us to understand QM - but neither has it equipped us to understand stochastic finance, which, interestingly, and merely as an aside, has mathematical parallels.

    Its just the human condition - nothing really earth shattering about it.

    Thanks
    Bill
     
    Last edited: Nov 29, 2013
  6. Dec 1, 2013 #5

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    ... "un-intended"?
    I would have thought that every result is "un-intended", otherwise certain persons may infer that you mean there is a designer (or Designer) who is doing the intending. It's probably useful to avoid the looser terminology around evolution and adaptations - and a good exercise: can you rephrase the idea without implying an intelligent agency?

    People confused on this issue may benifit from this TED-Ed animation ... though it still manages to continue the impression that evolution is a linear step-by-step process.
     
  7. Dec 1, 2013 #6

    Pythagorean

    User Avatar
    Gold Member

    I think the basic point of the OP quote is just that determinism and continuity (concepts of classical physics) are extremely intuitive to humans, and have (arguably) been selected for as part of motion prediction and spatial navigation. There probably aren't many predator or prey that behave like quantum particles.
     
  8. Dec 1, 2013 #7

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    @arunshankar: time for feedback - any of this any use to you?
     
  9. Dec 16, 2013 #8
    In biological terms, the brain is mostly the result of sexual selection of optimal foraging. Different brains in different organisms can be measured much like an intel processor, in terms of Mhz. However we need to go in deeper and ask why behaviour at all.

    "Evolutionary Psychology" and "Ethology" deal with this.

    This can be demonstrated through mapping neural correlates of consciousness in humans and understanding animal behaviour (Humans are animals). Basically gene/brain/action correlates. Then trying to understand the environmental influences on the phenotype.

    It is especially useful for understanding how humans cope with shaping their environment so quickly. For example, many of us have fears of things which don't even exist in our environment, but maybe in others. Snakes, spiders, reptiles, etc. Yet statistically the things which kill us the most in the developed world (overdoses, car crashes) are things we seem to have no natural inhibition against. There is an evolutionary explanation for this, however something else is happening. Namely behavior is a phenotype from an expressed genotype. This means our ability to catch a ball in our hand, all of that coordination has basically been trial and error throughout its evolutionary history via natural selection. So our brains are very much adapted for survival in the environment it is found in. However given we can shape our environment so quickly, we are now faced with new environments where our brains are less adapted. This can include comprehending new frontiers (the mental environment of say quantum mechanic theory) which our brains are not suited for, however oddly enough, the theory of evolution is saying nothing is stopping selection from modifying brains to be better at QM, if it confers a fitness advantage. I.e - People who understand QM can only reproduce. Those who are fitter reproduce more. Incremental changes over long periods of time.
     
  10. Dec 16, 2013 #9

    Evo

    User Avatar

    Staff: Mentor

    Please post the peer reviewed research on all of this, you know the rules.
     
  11. Dec 16, 2013 #10
    This guy, Kraus, is not a biologist. He's a theoretical physicist and cosmologist, and it seems he's a pal of Richard Dawkins, and on the same bandwagon as Dawkins to squelch mystical thinking. That's fine, but it can lead to generating a lot of edgy, meme-ful quotes that are probably more controversial than enlightning:

    http://www.goodreads.com/author/quotes/1410.Lawrence_M_Krauss
     
  12. Dec 17, 2013 #11
    Brain evolution through sexual selection and optimal foraging in Life History are not just peer-review, they are textbook concept learned in Evolution 101. Very simple basic stuff.

    Evolutionary psychology and the brain, Bradley Duchaine author, Leda Cosmides, John Tooby in Current Opinion in Neurobiology.

    Information and its use by animals in evolutionary ecology Sasha Dall in Trends in Eco & Evo.

    The handbook of evolutionary psychology by Kaplan covers it in Life History Theory and Evolutionary Psychology (50+ citations).

    However if u are new to biology and asking what all this stuff is the best way to learn this stuff is to try 1st year biology textbooks on Life History.
     
  13. Dec 17, 2013 #12
    I believe the OP must be referring to this video I found:



    Having watched it, I think Kraus is wrong to say we didn't evolve to understand QM, due to what he says later about us enjoying puzzle solving so much. Clearly there's been selection in favor of puzzle solvers, and QM is just another puzzle. Figuring things out is what we do, and it's not an activity limited to humans. A lot of animals are puzzle solvers, to the best of their ability.
     
    Last edited by a moderator: Sep 25, 2014
  14. Dec 17, 2013 #13

    Pythagorean

    User Avatar
    Gold Member

    Can you show any evidence to back of the claim that "clearly there's been selection in favor of puzzle solvers" that's specific enough to pertain to something like QM?
     
  15. Dec 17, 2013 #14
    Pythagorean - all the peer review papers above I listed contain puzzle solving related material. Zoobyeshoe is right.

    Remember, as kids we can't solve some things adults can. This is because developmentally we haven't grown the parts we need, irrespective of how much environmental influence (teaching) we receive. This means there is an organic bases to problem solving.

    Same with different animals with different brain sizes and complexity. They problem solve differently because of this.

    Selection must happen where there is genetic variation to confer a fitness advantage. Obviously there must be something to brain size/complexity. This is covered also under something called body/brain ratios! :)
     
  16. Dec 17, 2013 #15

    Pythagorean

    User Avatar
    Gold Member

    You're required to post links to your peer review research in this forum. It's also a common courtesy to quote the paragraph that makes your point.

    I saw you mentioned evolutionary psychology... but evolutionary psychology has experience a lot of criticism from traditional evolutionary fields. There's no method I know of that can verify a claim like "puzzle solving was selected for". And this is one of the main criticisms of evolutionary psychology: in traditional evolutionary literature, molecular evidence is favored, but there is no molecular evidence available for claims made in evolutionary psychology.
     
  17. Dec 17, 2013 #16
    That's an argument from incredulity.

    In evolutionary biology lots of lines of evidence, not just molecular, is favoured.

    Evolutionary psychology also apples to other organisms. Ethology has a history of testing things like peck responses and this is MEASURED by fitness, sometimes they use even inclusive fitness models. This include genetic analysis. Since genes produce proteins, there you have a molecular bases.

    Why not actually just have a look at the handbook I quoted. I can't post to full peer-review as that is paid for, but the handbook stuff I mentioned is available and very well referenced.


    BTW - Evolutionary psychology has no more or less criticism than any other field in evolutionary biology. I think maybe you are talking about some problems between Wilson and other Harvard biologists. What they are arguing against is genetic/biological determinism. Of course no one is saying any such thing.

    P.S.S - You aren't going to capture brain evolution in a few quotes. You need a full paper or better yet a manual/textbook that covers it, as per above.
     
    Last edited: Dec 17, 2013
  18. Dec 17, 2013 #17

    Pythagorean

    User Avatar
    Gold Member

    I'm not making an argument; I'm questioning an assertion that's already been made and asking for a specific argument with citations and quotes rather than a list of literature on a whole subject.

    The argument may be right, I don't know... but I'm not going to believe it under the pretense that it's somewhere in the millions of words you cited as evidence.
     
  19. Dec 17, 2013 #18
    I can't provide a peer review paper which says ""clearly there's been selection in favor of puzzle solvers that's specific enough to pertain to something like QM?"

    That's not going to happen. All I can do is show the various linking disciplines (and its only a few things I referenced there) and how they integrate to explain such a massive question like "How did the brain evolve" let alone "How did the brain evolve to do QM". Also we are talking about brains (plural among living things) and also developmental biology (growth).

    I have had to read lots of papers on here from people to understand something like the different interpretations of QM etc. Sometimes its going to take more than just a quote and this is one of them. However if someone can do better than I, then have at it. :)
     
  20. Dec 17, 2013 #19
    If you have genetic variation, reproduction and the struggle for survival, evolution MUST occur by definition. However there are models of evolution, like neutral selection, where no adaptive evolution occurs but the genome changes. In the real world, stasis is almost unheard of, although evolution can occur very slowly.
     
  21. Dec 17, 2013 #20

    Evo

    User Avatar

    Staff: Mentor

    Annihilator, it's a rule that when you make claims that you post the valid scientific sources, I am not asking for me, I am advising you that you must provide them.

    Now, please post acceptable exerpts from these books showing page and paragraph information that specifically backs up what you posted.

    Also, text speak is not allowed on this forum.
     
  22. Dec 17, 2013 #21
    Why are you even asking? Do you doubt better puzzle solving skills represent an advantage? The opposite assertion, "It's clear those with the poorer puzzle solving skills are better at finding food and shelter, and escaping from traps and dangerous situations, and therefore live longer to pass their genes down," would be a ridiculous assertion.

    And I didn't even imply such selection was specifically aimed at QM. I characterized QM as a puzzle, like any other.
     
  23. Dec 17, 2013 #22

    phinds

    User Avatar
    Gold Member

    Yes, but QM is NOT a puzzle like any other. It involves concepts that are so far outside our day to day experiences that I don't think your logic follows. Our puzzle solving ability evolved to deal with experiences in what we would commonly think of as our "real world day to day experiences" and QM does not fall in that domain at all.
     
  24. Dec 17, 2013 #23

    Ygggdrasil

    User Avatar
    Science Advisor
    2017 Award

    Humans came about because of evolution. Some humans understand quantum mechanics. Therefore, evolution must have enabled us to attain the intelligence to understand QM.

    One thing that I think that Krauss gets wrong in his quote is his statement (from the OP) that "you know how to throw a rock or a spear or how to find a cave." While it might make sense for behaviors and patterns of thinking be hardwired into our brains, they are not. None of these behaviors are instinctual. Like understanding QM, all of these behaviors are learned.

    Indeed, while there is some large-scale organization to the brain that evolution has hard-wired, most of the connections in our brain form in response to experiences that occur to us throughout our lives. While this means that we are born with very few instinctual behaviors (and as a result human babies cannot survive without a caretaker), this wiring strategy allows our brains to adapt to new situations and gives humans an unparallelled ability to learn. A striking example of this plasticity is experiments done on perceptual adaptation. For example, if an individual wears a pair of reversing glasses that inverts one's field of view such that up is down and down is up, the brain can eventually adapt and the wearer will begin to see the world right side up despite the fact that the wearer's vision remains inverted.

    The human brain has evolved a great deal of plasticity, and it is this ability to adapt to new circumstances that allows humans to learn such complicated ideas as quantum mechanics.
     
  25. Dec 17, 2013 #24
    I like Ygggdrasil's answer, and I will add that all of physics up to QM was, at first, completely outside our "real world day to day experiences". It took from the dawn of man till Galileo before we understood and articulated the first law of motion correctly, despite the fact we're constantly surrounded by motion. I would argue that QM only seems like the most baffling possible puzzle because it's the current one.
     
  26. Dec 17, 2013 #25

    Pythagorean

    User Avatar
    Gold Member

    Yes, evolution must have enabled us to attain the intelligence to understand QM. That can be said about any subject. But was the intuition to understand QM selected for? Of course not. It's easy to wiggle something like "puzzle-solving" into selection since it's a vague concept and I think it strays from the OP's topic anyway to talk about puzzle-solving in general.

    The intuition we (and most mammals) start with allowed us to track prey and avoid predators, to know our bodies position in space, to predict trajectories, to judge depth so we don't walk off cliffs. We have great spatial intuition in the classical physics sense. These are readily available for throwing a rock or spear (I don't agree with finding a cave... that would be more of a Bayesian process for a caveman.. still not QM though).

    But it's really not surprising... we framed classical physics in language and concepts that were intuitive to us from what we could observe. With better technology and advanced concepts, we were able to predict and observe things beyond what our senses could naturally observe and (still using abstractions like space) we formulated QM.

    QM concepts like nonlocality, indistinguishability, superposition of states... intuition for such concepts wouldn't have had any usefulness in reproduction in the 99.9% of human history. So it's not surprising that humans don't readily grasp them.
     
    Last edited: Dec 17, 2013
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook